Computer Graphics World

January 2009 14 ■ ■ ■ ■ CG Character standard rig. at wasn't appropriate for this performance capture, though. "Clearly, their rig wouldn't do," Barba says. "So, we built our rig in a way that we could give it to them and they could apply the curves to it." And, that was the last ingredient in the performance-capture soup. Image Metrics translated the movement of Pitt's face into animation curves and applied them to a rig that Digital Domain built using shapes de- rived from data that Mova had captured dur- ing the FACS session Pitt had done earlier. When the animators got the footage, they could see, attached to the small actors' bodies, the old faces and heads performing Pitt's dialog. "It wasn't a turnkey solution," Barba says of the performance capture. "It was a starting point for timing. ere are shots in the video where Brad Pitt is sitting and staring, and you know he's thinking. en you load up the rig. He's not doing anything, and he looks like a dead guy. at's where our animators came in." On Location To fi t the old heads onto the bodies of the small actors fi lmed during principal photography, the tracking team needed to locate the camera and the actor's head pre- cisely in 3D space within each shot. ey needed to do this for 325 head replacement shots. Each shot averaged 100 frames. During fi lming, data integration lead Jesse James Chisholm conducted an on-set sur- vey, measuring the main points, taking still images with a Canon 1DS, and collecting high-dynamic range (HDR) images—360- degree photographs of the set taken at mul- tiple exposures for each lighting setup—for lighting. e body actors wore custom-fi t- ted blue hoodies onto which tracking su- pervisor Marco Maldonado attached yellow markers in specifi c patterns. In addition to Fincher's A- and B-roll cameras, Maldonado added two Viper cam- eras as witness cameras on either side of the main camera. All the cameras were synced with time code and were gen-locked so the shutters were in sync as well. " e sync was a new process, but we felt doing that would save us time later," Maldonado says. e time code helped the team more easi- ly fi nd matching data streams from the cam- eras so they could do a visual check to see if the data was in sync. "We relied on that before we went into the calibration process," Maldonado says, referring to the method for deriving the motion for the cameras. "Once the cameras were calibrated, we oriented the dataset to the on-set survey point cloud," Maldonado continues. " at gave us all four cameras calibrated to the set in orientation, scale, and placement. We could see where they were in relation to, say, the Nolan house and front lawn; we could see in Maya that they were in the right place. en we did pattern tracking." By tracking patterns in the 2D foot- age, the software helped the crew locate in 3D space the small actor wearing the blue hoodie with the yellow dots. And, that made it possible to replace the person's hoodie head with the CG head. "We had 20 or 30 patterns on the actor's hoodie and face," Maldonado says. "If you track the same pattern of dots with four Eyes Right One artist on the crew worked full time on the eyes to get the "peeled grape" quality director David Fincher asked for on the surface. "There were some close- up shots in the plate that defi nitely scared us," says lighting supervisor Jonathan Litt. "So we asked the modelers for an extra touch. Our eye artist, who took high- defi nition footage of his own eyes, noticed the conjunctive layer, a netting that connects the skin in the corner to the eyeball. So we rigged this layer into the eye. When the eye turns to look in an extreme direction, this layer stretches and extends with the eye." For eye refl ections, the lighting artists used a hybrid of rendering and compos- iting. "We tried to give the compositors as much fl exibility as possible," Litt says. "Some eyes have straight 3D-rendered refl ections. Often, we needed serious adjustment in compositing for the eyes and the skin. The compositors didn't ad- just the lighting, but they balanced the skin tone and oily layer, and other optical effects." –Barbara Robertson Lighting artists duplicated the lights on set to fi t the digital head seamlessly into the background. hoodie and face," Maldonado says. "If you track the same pattern of dots with four hoodie and face," Maldonado says. "If you track the same pattern of dots with four pervisor Marco Maldonado attached yellow pervisor Marco Maldonado attached yellow markers in specifi c patterns. pervisor Marco Maldonado attached yellow markers in specifi c patterns. photography, the tracking team needed to locate the camera and the actor's head pre- photography, the tracking team needed to locate the camera and the actor's head pre- photography, the tracking team needed to locate the camera and the actor's head pre- hoodie and face," Maldonado says. "If you track the same pattern of dots with four hoodie and face," Maldonado says. "If you track the same pattern of dots with four pervisor Marco Maldonado attached yellow markers in specifi c patterns. photography, the tracking team needed to

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